Chapter 5 - Workbook Flashcards
What are protein threads that compose myofibrils called?
Muscle filament
Circular muscles that surround the eyelids are called what?
Oricularis oculi
What happens when actin and myosin filaments slide past each other?
Muscle contraction
A muscle that contracts to produce a particular action is called what?
Agonist
What are inward extensions of the plasma membrane that surround myofibrils called?
Transverse tubules
When a motor nerve is disconnected from a muscle, the muscle loses tone and becomes what?
Flaccid
What is the attachment of the muscle to the more movable bone called?
Insertion
Depolarization may cause an electrical impulse to be generated in the muscle fibre which travels across the plasma membrane and spread through the T tubules. What is the electrical impulse called?
Action potential
What is a contractile protein that forms thick filaments called?
Myosin
The trapezius extends what?
The head and neck
What is the basic unit of muscle made of actin and myosin filaments?
Sarcomere
What are interwoven filaments that join sarcomeres at their ends called?
Z line
What is a contraction in which muscle tension increases, but muscle length does not change called?
Isometric
What is a muscle that produces the opposite movement to an agonist called?
Antagonist
Skeletal muscles produce movement by pulling on these, which pull on the bones. What are these?
Tendons
What is the connective tissue that wraps a fascicle called?
Perimysium
What is a cross-bridge?
Links actin and myosin filaments
What are the cells that make up each skeletal muscle called?
Muscle fibres
What is a bundle of muscle fibres called?
Fascicle
What is the connective tissue that covers a muscle called?
Epimysium
Which neurotransmitter is released into the synaptic cleft between the motor neuron and the muscle fibre?
Acetylcholine
When additional energy is required, what is stored in muscle cells that is degraded to yield glucose?
Glycogen
What is a junction between neurons or between a neuron and an effector?
Synapses
A contraction in which muscle shortens and thickens as it contracts while the muscle tone remains the same is called what?
Isotonic
The deltoid abducts what?
The upper arm
Depolarization of the T tubules triggers the release of what stored ion?
Calcium
Muscles maintain a state of partial contraction called what?
Muscle tone
What muscle flexes and adducts the leg?
Sartorius
What is a contractile protein that forms thin filaments called?
Actin
Muscle fibres stockpile something, which can transfer its stored energy to ATP as needed. What is the something?
Creatine Phosphate
Release of inorganic phosphate from the myosin causes what?
Cross-bridges to flex
What is another name for a prime mover?
Agonist
In depolarization, calcium ions bind to the proteins on what?
Actin filament
Which two muscles raise the jaw?
Masseter and temporalis
What is the connective tissue that covers individual muscle fibres called?
Endomysium
What fixes the origin of the prime mover so that its force is fully directed on the bone on which it inserts called?
Fixator
The large, superficial muscle that extends the thigh and rotates the thigh medially at the hip is called what?
Gluteus
What kind of nerve transmits impulses to muscle fibres, signalling them to contract?
Motor nerves
The tibialis dorsiflexes what?
The foot at the ankle
The oricularis oris closes and protrudes what?
The lips
What increases the volume of the chest cavity in inspiration?
Diaphragm
What is it called when one muscle moves an arm and another muscle undoes the motion?
Antagonistic
What surrounds the muscle and merges with the tissues of the tendon?
The fascia
What is a voluntary muscle attached to bone called?
Skeletal muscle
What stabilizes joints so that undesirable movement does not occur?
Synergist
Acetylcholine diffuses across the synaptic cleft and combines with receptors on the surface of the muscle fibre causing what?
Depolarization
When muscle cells break down glucose by anaerobic metabolism, what is a waste product?
Lactic acid
What are the tough cords of connective tissue that anchor muscles to bones?
Tendons
Release of inorganic phosphate from what causes the cross-bridges to flex?
Myosin
What extends the forearm at the elbow?
The triceps brachii
What is the pattern of transverse bands made up of overlapping muscle filaments called?
Striation
Which muscles flex the leg at the knee?
Gastrocnemius
When binding sites are exposed, ATP is split and energy is released which energizes what?
Myosin
Attachment to a less movable bone is called what?
Origin
What do neurotransmitters send signals across?
Synapses
What is a threadlike structure that runs lengthwise through the muscle fibre called?
Myofibril
